lean2/src/library/expr_lt.cpp

171 lines
6.2 KiB
C++

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "kernel/expr.h"
#include "library/expr_lt.h"
namespace lean {
bool is_lt(expr const & a, expr const & b, bool use_hash) {
if (is_eqp(a, b)) return false;
unsigned wa = get_weight(a);
unsigned wb = get_weight(b);
if (wa < wb) return true;
if (wa > wb) return false;
if (a.kind() != b.kind()) return a.kind() < b.kind();
if (use_hash) {
if (a.hash() < b.hash()) return true;
if (a.hash() > b.hash()) return false;
}
if (a == b) return false;
switch (a.kind()) {
case expr_kind::Var:
return var_idx(a) < var_idx(b);
case expr_kind::Constant:
if (const_name(a) != const_name(b))
return const_name(a) < const_name(b);
else
return is_lt(const_levels(a), const_levels(b), use_hash);
case expr_kind::App:
if (app_fn(a) != app_fn(b))
return is_lt(app_fn(a), app_fn(b), use_hash);
else
return is_lt(app_arg(a), app_arg(b), use_hash);
case expr_kind::Lambda: case expr_kind::Pi:
if (binding_domain(a) != binding_domain(b))
return is_lt(binding_domain(a), binding_domain(b), use_hash);
else
return is_lt(binding_body(a), binding_body(b), use_hash);
case expr_kind::Sort:
return is_lt(sort_level(a), sort_level(b), use_hash);
case expr_kind::Local: case expr_kind::Meta:
if (mlocal_name(a) != mlocal_name(b))
return mlocal_name(a) < mlocal_name(b);
else
return is_lt(mlocal_type(a), mlocal_type(b), use_hash);
case expr_kind::Macro:
if (macro_def(a) != macro_def(b))
return macro_def(a) < macro_def(b);
if (macro_num_args(a) != macro_num_args(b))
return macro_num_args(a) < macro_num_args(b);
for (unsigned i = 0; i < macro_num_args(a); i++) {
if (macro_arg(a, i) != macro_arg(b, i))
return is_lt(macro_arg(a, i), macro_arg(b, i), use_hash);
}
return false;
}
lean_unreachable(); // LCOV_EXCL_LINE
}
bool is_lt_no_level_params(level const & a, level const & b) {
if (is_eqp(a, b)) return false;
if (kind(a) != kind(b)) {
if (kind(a) == level_kind::Param || kind(b) == level_kind::Param)
return false;
return kind(a) < kind(b);
}
switch (kind(a)) {
case level_kind::Zero:
lean_unreachable(); // LCOV_EXCL_LINE
case level_kind::Param:
return false;
case level_kind::Global:
return global_id(a) < global_id(b);
case level_kind::Meta:
return meta_id(a) < meta_id(b);
case level_kind::Max:
if (is_lt_no_level_params(max_lhs(a), max_lhs(b)))
return true;
else if (is_lt_no_level_params(max_lhs(b), max_lhs(a)))
return false;
else
return is_lt_no_level_params(max_rhs(a), max_rhs(b));
case level_kind::IMax:
if (is_lt_no_level_params(imax_lhs(a), imax_lhs(b)))
return true;
else if (is_lt_no_level_params(imax_lhs(b), imax_lhs(a)))
return false;
else
return is_lt_no_level_params(imax_rhs(a), imax_rhs(b));
case level_kind::Succ:
return is_lt_no_level_params(succ_of(a), succ_of(b));
}
lean_unreachable();
}
bool is_lt_no_level_params(levels const & as, levels const & bs) {
if (is_nil(as))
return !is_nil(bs);
else if (is_nil(bs))
return false;
else if (is_lt_no_level_params(car(as), car(bs)))
return true;
else if (is_lt_no_level_params(car(bs), car(as)))
return false;
else
return is_lt_no_level_params(cdr(as), cdr(bs));
}
bool is_lt_no_level_params(expr const & a, expr const & b) {
if (is_eqp(a, b)) return false;
unsigned wa = get_weight(a);
unsigned wb = get_weight(b);
if (wa < wb) return true;
if (wa > wb) return false;
if (a.kind() != b.kind()) return a.kind() < b.kind();
switch (a.kind()) {
case expr_kind::Var:
return var_idx(a) < var_idx(b);
case expr_kind::Constant:
if (const_name(a) != const_name(b))
return const_name(a) < const_name(b);
else
return is_lt_no_level_params(const_levels(a), const_levels(b));
case expr_kind::App:
if (is_lt_no_level_params(app_fn(a), app_fn(b)))
return true;
else if (is_lt_no_level_params(app_fn(b), app_fn(a)))
return false;
else
return is_lt_no_level_params(app_arg(a), app_arg(b));
case expr_kind::Lambda: case expr_kind::Pi:
if (is_lt_no_level_params(binding_domain(a), binding_domain(b)))
return true;
else if (is_lt_no_level_params(binding_domain(b), binding_domain(a)))
return false;
else
return is_lt_no_level_params(binding_body(a), binding_body(b));
case expr_kind::Sort:
return is_lt_no_level_params(sort_level(a), sort_level(b));
case expr_kind::Local: case expr_kind::Meta:
if (mlocal_name(a) != mlocal_name(b))
return mlocal_name(a) < mlocal_name(b);
else
return is_lt_no_level_params(mlocal_type(a), mlocal_type(b));
case expr_kind::Macro:
if (macro_def(a) != macro_def(b))
return macro_def(a) < macro_def(b);
if (macro_num_args(a) != macro_num_args(b))
return macro_num_args(a) < macro_num_args(b);
for (unsigned i = 0; i < macro_num_args(a); i++) {
if (is_lt_no_level_params(macro_arg(a, i), macro_arg(b, i)))
return true;
else if (is_lt_no_level_params(macro_arg(b, i), macro_arg(a, i)))
return false;
}
return false;
}
lean_unreachable();
}
int expr_cmp_no_level_params::operator()(expr const & e1, expr const & e2) const {
if (is_lt_no_level_params(e1, e2))
return -1;
else if (is_lt_no_level_params(e2, e1))
return 1;
else
return 0;
}
}